MTHFR and male infertility: With regard to the MTHFR C677T mutation, Gupta N et al.14 performed a meta-analysis which included 13 articles and concluded that MTHFR C677T was strongly associated with male infertility; however, the conclusions were inconsistent with the results from a more recent meta-analysis conducted by Weiner As et al. in 2014 that analyzed the same number of studies15.